Elevator-control apparatus



Aprillfi, 1929. v c, w BASSETT 1,709,301

ELEVATOR CONTROL APPARATUS Filed April 13, 1927 5 Sheets-Sheet 1 April 16, 1929.

c. w. BASSETT 1,709,301

ELEVATOR CONTROL APPARATUS Filed April 13, 1927 5 Sheets-Sheet 2 @Q u fifli JUL "9 9- L; I

P2 it q Q g x l k v a lNVENTOR April 1929- c. w. BASSETT ELEVATOR CONTROL APPARATUS Fi gd April 13, 1927 5 Sheets-Sheet 5 1 w I $55.: R

April 16, 1929. c, w BASSETT 1,709,301

ELEVATOR CONTROL APPARATUS Filed April 13. 1927 5 Sheets-Sheet 4 I uvmvron. 67/?06 W 6176:3[77

April 16,1929. c. w. BASSETT ELEVATOR CONTROL APPARATUS INVENTOR.

5 Sheets-Sheet ATTO EY.

Filed April 13, 1927 l atented Apr. 16, 1929.

entree STATES PATENT OFFICE.

CYRUS XV. BASSETT, OF MONTKJLAIR, NEW JERSEY, ASSIG'NOR T ELEVATOR SUPPLIES COMPANY, INC., 0F HOBOKEN, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ELEVATOR-CONTROL APPARATUS.

Application filed April 13,

his invention relates to elevators and particularly to elevators electrically controlled, whether such control is centered in the car or is distributed at the various floors. lVhile many oi? the features of the invention may be embodied in elevator systems with other types 0t control, the invention is particularly well suited for use in connection with the so-called push button elevator operating on principles well known in the art.

More particularly an object of theinvention is to provide novel and efficient door operating mechanism for automatically controlling the door or gate on the elevator and also. itdesired, the doors at the various landings. In this connection a feature of the invention lies in the provision of novel means for rendering the operation of the doors send-automatic and for controlling this semi-automatic operation electrically by means operated incidentally to the operation of the control means by the user of the elevator.

To carry out the objects of the invention 1 provide a self-holding device for the ole a'tor door or gate. and another such device for each landing door, if desired, which device maintains the door in' any position to which it has been moved so that it is unnecessary for the person entering or leaving the elevator to devote his attention and his strength to the tai of manually holding the doors. This self-holding device in itself constitutes a decided improvement in elevator operation and solves a problem which has been a vexatious and diliicult one up to the present time.

llereto'l'ore elevators of this type, in common with most other elevators, have been provided with devices whereby the doors always tend to assume the closed position, unless physical restraint is thought to bear thereupon by the user oi the car. This puts a burden on the user of the car which is often times distressing, particularly when the user of the car is also under the necessitv oi carrying luggage or other articles; With the use of the holding device described herewith such a burden is removed from the user so that he is tree to enter and leave the car without paying any attention to the doors, except for the initial act of opening the doors to enter or leave the elevaton This holding device, however, is only one 1927. Serial No. 183,497.

part of the present invention. Another important feature of the invention, as suggested above, is the provision of semi-automatic control means for all of the holding devices, which operate to release the sell-acting holding devices thru the instrumentality preferably of electrical means energized as an incident to the operation of the controlling devices of the elevator proper, such as push buttons in the car and at the various landings.

Other objects and advantages to be derived i'rom the use of the present invention or the component parts thereof lie in the specific constructions, combination and arrangement of said parts and will become more apparent from the following description when read with reference to the recompanying drawings, wherein:

Figure 1 is a view of an elevator equipped with the novel apparatus of this invention.

Figure 2 is a View, partly in section, showing some of the parts in Figure 1 on a larger scale. s

Figure 3 is a still larger view of the holding device.

Figure it is a schematic showing of a preferred type of control means for an elevator installation utilizing the door controlling apparatus shown in Figures 1, 2 and 3.

Figure 5 is a view in elevation of a hatchway or landing door to which shown connocted the novel apparatus of this invention.

FigureG is a side elevation, partly in section, of the parts shown in Figure 5, to-' gether with a side elevation of the parts shown in Figure 1 as they appear when the elevator is in a position opposite the land door, the latter part of the movement being checked by suitable means, usually liquid,

in the lower part of the cylinder. Such a device is well-known in the art, a deas shown at 23.

tailed description of a suitable door closer and check for this purpose being given in aatent to Necks, No. 1,530,96 l, granted March 24', 1925. Consequently no claim is made herein to this door closing cylinder per so, which forms part of this in. nation only in its co-action and inter-relation with the novel parts presently to be described.

When it is desired to operate the'landing doors, as for example the door 2, shown in Figures and 6, as well as the elevator gate 2, shown in Figure 1, there may be provided a second door closer and check unit similar in all respects to the closer and check unit 3 shown in Figure 1. Such a unit for closing and checking the door 2 is indicated at 3 in Figures 5 and 6. It will be understood that the mechanism associated with the closer unit 3 shown in Figures to 25 inclusive and presently to be described in detail, can be duplicated in all respects when it is desired to control the landing doors as well as the gate of the elevator itself, and the equipment so duplicated is preferably arranged as shown in Figures 5and 6. It is further to be un derstood that similar apparatus may be provided at each of the other landings (not shown) at which the elevator stops.

Suitable means are shown for transmit ting the effect of the movement of the piston in the door closer 3 to the gate 2. As shown in Figures 2 and 3 these connections comprise the piston rod 6 suitably guided in bearings? andS in the frame 5, a crosshead 9 fixed for movement with the rod 6, and a connecting rod 10 pivoted at one end to the crosshead 9 and at the other to the bell crank 11, the latter being in turn pivotally fixed'on bearing 12. Extending from the bell crank 11 is the operating arm 13 connecting by means of link 14 with the bracket 15 on theouter edge of gate 2.

Crosshead 9 in addition to being fixed to rod 6 is also fixed to a piston rod 18, which is preferably mounted in substantial narallelism with piston rod 6 and is similarly guidedthru bearing 7. This piston rod 18 extends downwardly into the gate holding device, designated by the reference charac ter 19. This gate holding "device, which forms one of the most essential parts of the invention, acts to positively maintain the piston rod 6, hence the gate 2, in whatever position the former is moved to. In the preferred form the holding device 19 comprises a substantiall cylindrical chamber 20 and another, and preferablysmaller, chamber 21, also cylindrical, the two chambers being substantially parallel to each other, as shown in Figure 3. In chamber 20 is a piston 22 to which the piston rod 18 is suitably fixed, Piston 22 preferably has ar'substantially fluid tight lit in the cylinder 20. Such a fit may be obtained in any suitable way but as illustrated it is obtained partly by the provision of expander rings 24, which fit in the circumferential surface of the piston As shown the piston is somewhat hollow in construction, not for the purpose of providing for oscillation, but merely for economy of material. Obviously other shapes and constructions could be employed.

In the lower portion of the piston chamber 20 is mounted a valve member 25 provided with a pair of vertically disposed passages 26 and 27, having suitable seats provided therein for the reception of ball check valves 28 and 29 normally preventing passage of fluid therethrough in the downward direction. In the preferred form as illustrated the valve 25 is provided with a spiderlike construction in its lower portion so as to provide clear passage of fluid from the valve chamber 21 thru the underside of the valve to the piston chamber 20, the connect ing passage fonthis purpose being shown at 80. The valve 25 is maintained against a shoulder 31 in the wall of cylinder 20 preferably by means of the externally threaded nut 32 provided with a fiatsided hole 33 serving for the insertion of a wrench or other suitable means, by which .it may be threaded up into engagement with the valve 25 to push the latter against its shoulder 31 in the wall of cylinder 20. After insertion of the valve 25 and the retaining nut 32, the cylinder is closed at its bottom end by suitable means such as the externally threaded'plug 38 having a head 39 on which is placed a gasket or other equivalentmeans for forming a seal between the head 39 and the body of the holding device.

The valve chamber portion 21 ot the holding device is preferably similarly closed at the lower end by means of another plug 40 similar to plug just described. In the valve chamber 21 is mounted a long tubular valve member 42 suspended on the valve rod by suitable means such as an internally threaded thimble i3 adapted to engage the correspondingly threaded member l i, which serves to retain the valve stem by means of the head 4i?) provided on the latter. its shown, the tubular valve member 42 is formed integrally with the thiinble portion just described and is provided with ports it? in the upper portion of its tubular wall. hese ports provide free passage of the liquid or other checking fluid employed from the upper portion ofthe valve chamber 21' into the internal portion of the valve member 42 and thence downwardly into the lower chamber 5%, from which point the liquid may pass bacl: into the piston cham ber thru the valve 25. Su'tilcient clearance is allowedbetween the valve thimble L3 and the wall of the chamber 21 to permit fairly free passage of the liquid in the course just described.

The valve member 42 is suitably guided by means of the sleeve (50, which in the preferred form as illustrated has a very tight fit against a shoulder 62 in the wall of chamber21. Some clearance is provided between the valve stem 4:5 and the retaii'iing nut ll, also between the head 49 and the inner surface of the valve thimble 43, to allow for a certain amount of angularity in the movement of the valve stem 45, which extends upwardly thru the cap 65, stalling box (56 and rubber bumper ($7, to be lixedly secured by means of a suitable thread or otherwise, as indicated at (38, to the lug 69, to which is pivoted a rocker arm T0 fulcrulned on bearing 71 and having attached to its other end suitable means for effecting operation of the valve stem d5. In the preferred form, as

illustrated, this operating means comprises a solenoid 75 suitably mounted in the framewerk 5 and provided with a plunger nor mally held in the upward position, in which position it is maintained by means oil suit able connections, such as pin 76, with the lug 77 pivoted on rocker arm 70.

Suitable means, such as spring 80, serves to retain the rocker arm and the plunger pin 76 in the extreme upward position, as shown, and energization of the solenoid causes an attraction of the plunger and hence a. downward movement of the plunger pin 76 against the force of spring 80.

'Vv'ith this construction it will be apparent that (assuming the holding device to be completely filled with a liquid, preferably a viscous liquid such as oil or glycerine) a movement of the crosshead 9 in the upward direction (corresponding to a movement of the gate 2 toward open position) will cause upward movement of the piston in the door closingcylinder 3 and will also cause upward movement of the piston 22 in the chamber 20 of the holding device, the movement of these two pistons being eli'ected, as is obvious, by means of the connecting piston rods 6 and 18. Now, since the holding device is completely (or substantially so) filled with liquid, and also since the valve is in its normal (downward) position as shown in the drawings, the upward movement oi? the piston 22 will create a very low pressure approaching a vacuum on the under side of the piston so thatl'he liquid will illow thru passage into the upper portion of the valve chamber 21, thence downwardly in said chamber and thru the ports 50 in the wall of the tubular valve member to the lower portion of the chamber 21, thence thru passage 30 and vertical passages 26 and 27 of the valve 25 back to the chamber 20 on the under side of the piston 22.

Now due to the construction of the valve 25 and the provision or the ball check valves 28 and 29 therein, it is obvious that the liquid which flows in an upward direction thru said valve in the manner just described and by reason of pressure exerted thru the liquid by virtue of the upward movement of the piston 22, cannot flow back againt but is trapped in the lower portion of the piston chamber 20, completely filling the entire chamber up as far as the lower end oi the piston. Consequently it is obvious that as soonas the upward movement of the crosshead 9 ceases, irrespective of the distance it has traveled, whether a full stroke or only a portion there of, a return, that is, downward movement of the piston will be impossible to any appreciable extent with the tubular valve member i2 in the position shown in the drawings and with the ball check valves resting on their seats as shown, in which positions they will of course remain since the force holding them in such-position is greater than the force tending to push them upward. It is then obvious that despite the tendency of the spring in the door closer cylinder 3 to return the piston rod 6 to its lowermost position such a return will be impossible, hence movement of the gate 2 in a direction to close will be impossible, while and so long as the valve remains in the position shown, in which position the solenoid 75 is de-energized.

Upon energization of the solenoid 75, however, the rocker arm is tilted about its fulcrum against the force of spring 80 and the valve stem 45 is thereby raised carrying with it the tubular valve member 42 which rises to the position indicated in dash lines, Figure 3. In this raised position of the valve member it will be apparent that the liquid in chamber 20, below the piston 22, has a means of escape as the piston 22, together with the piston in the door closing cylinder 3, descends, this free passage being thru the horizontal channel 81, around the lower end of the tubular member, thence up thru the tubular member and the lateral ports 5011p thru the chamber 21 and back into the free space in the upper portion of the chamber 20 above the piston 22, the flow taking place along the course just described by reason of the difference in pressure produced in the two chambers by virtue of the downward movement of the piston 22, which downward movement is produced, it will be remembered, by reason of the spring or other equivalent means in the door closing cylinder 3 which is now free, due to the removal of the liquid resistance to cause the descent of the two connected pistons.

It is to be noted that cushioning means are provided to prevent too sudden or too noisy operation upon the energization of the solenoid 7 5. This means, as illustrated, comprises a cup like member 81 secured by suitablemeans, such as set screws, to the valve stem 15 and movable therewith to envelop the downwardly extending projection 7 9 on the. cap member 65 as the valve stem ascends in response to movement of the rocker arm 70. at suitable vent or outlet port 82 is provided in this cup member 81 to allow gradual escape of the liquid imprisoned in the cup member as the latter envelops the projection 7 9. Obviously the size of this outlet will govern the degree of retardation and cushioning obtained as the solenoid operates.

l have now described in detail the preferred form of gate closing and holding means. It remains merely to state that each hatcln 'way door may likewise be equipped with apparatus duplicating that herein described with particular reference to the elevator gate and illustrated in Figures 5 and 6 as it appears with relation with one such hatchwaydoorfl and further to state that the solenoid 75,-or other electric or electro-magnetic releasing meansis to be interconnected with the control circuits passing to the hoisting motor from the button or lever operated switches commonly furnished in the elevator car and atthe landings, so as to cause the operation of said releasing means as. an incident to the initiation of the elevator control. means. A brief description will now be given of the preferred method of efiiecting such control, reference being had to Figure 1, wherein a two-stop push button control is schematically shown, by

cuits arranged as shown the energization 0- way of illustration.

Push-buttons located in the elevator are represented at and 91, button 90 serving to send the elevator to the first floor, and button 91 to send it to the second floor. Similar calling means are shown at 92 and 93 92 being the button at the first floor landing, and 93 the second iioor. 9% is a relay provided for maintaining a circuit in shunt around either push button 91 or 98; the contact operated by the relay 94cbeing shown at 95. Similarly relay 90 serves to maintain a. circuit in shunt around either button 90 or 92 after one of these buttons has been actuated; the contact operated by relay 96 being shown at 97. The solenoid 75 previously described is shown diagrammatically in Figure 4; and desi nated with that reference character. It is further to be understood that when the controlling apparatus of this invention is duplicated at the landings for operation of the landingdoors, such as door 2 shown in Figure 5, the duplicate solenoids such as solenoid 75 shown in Figure 5 will be so connected electrically with thecar calling circuits as to be energized simultaneously with the energization of solenoid 75, the latter being controlled electrically in the manner now to be described in detail as follows. lV'th the cirsolenoid 75 is shown directly controlled by means of the normally opened contacts shown at 98 and 99, contact 98 being arranged so as to close on energization of relay 9% and the contact 99 similarly operated by relay 96. Relay 100, when energized in the manner presently to be described, serves to open the circuit thru solenoid 7 5 at contact 101. The circuit to relay 100 in turn is controlledby either the contacts 102 or the contacts 103, the former operating in response to the energization of relay 10 i and the latter in response to the energization of relay 105.

Reference character 106 designates what is commonly termed an interlocking switch designed to assume the closed position when the elevator gate assumes closed position. CharacterlOY indicates an additional contact perated by relay 96 and serves an interlocking or non-interferencc switch, provided for the purpose of rendering all other control buttons ineffective during the time the elevator is under the control of either buttons 91 or 98 previously operated. Similarly contact 108 operated by relay 9st serves the same function with reference to' push buttons 90 and 92. Switches 1.09 and 110 representselector switches serving to stop the movement of the elevator by opening the control circuits when the car has reached a predetermined level.

Characters 111, 111 112 and 113 represent respectively the conventional overtravel, slack cable and emergency stop switches. The contacts operated by the commonly used reversing switches are shown at 114 and 115, the contacts at 1141: controlling movement of the car in the up direction and those at 115 controlling movement. in the down direction; the up contacts closing. upon energization of the up relay 104-. and the down contacts closing upon energization of the down relay 105. The hoisting motor armature is shown diagrammatically' at 116, the shunt and series fields for the motor being indicated at 117 and 118 rcspccly, and the brake solenoid at 119. With ti .0 arr-air. ement of the controlling means the operation is as follows:

Let it be assumed that the car is the floor where it has been left with the car gate 2 in the open position, in which position it held by virtue of the holding means previously described. Now let it be fur her assumed that a person is on the second floor and desiring to call the car to that floor presses the appropriate button 93. Uperation or" this button 93 causes a. circuit to be closed from the positive teed, thru switches 111, 112, 113 and contacts operated by button 93, thence thru selector switch 109, switch 107 andrelay 9i back to the negative feed by way of conductor 120.

Energization of relay 94 thus produced causes closure of the contacts 95 and 98 and opening of contacts at 108. Closure of contacts at 95 forms a maintaining circuit in way of the conductors including the switches 111, 112, 113, 95, 109, 107 the relay 91 and conductor 120. At the same time the opening of the contacts at 108 prevents any effectiveioperation of either push button 90 or 92 during the time the elevator remains under the control of the means initiated by the operation of the button 98. In this connection it is to be understood that if there are additional floors, noninterference switches similar to switch 108 will be provided for each of such floors and for a similar purpose.

The closing of contacts at 98, which, as just described, is effected by the energization of relay 94, causes a circuit to be closed thru a relay 75, such circuit passing from the positive feed thru conductor 121, contacts at 98, gate releasing solenoid 75, and switch 101, back to the negative line by way of con ductor 120. The energization of the gate releasing solenoid thus produced causes release of the gate holding means and the resultant closure of the gate 2 thru the instrumentality of the gate closing device previously described in detail. Now, as soon as gate 2 reaches fully closed position, the interlock switch 106 operated by said gate likewise assumes closed position and thereby completes a circuit thru relay 10*1, passing from positive feed th'ru conductors 121, 122, switches 95, 109 and 107, thence thru relay 10a and normally closed switch 128, thence back to the negative feed by way of interlock switch 106 and conductor 120.

The energization of up relay 10% thus produced causes the closing of the triple set of contacts 114 which are controlled by said relay 10st. Closing of cont-acts at 114; causes the energization of the hoisting means by reason of the circuits thus completed and passing as follows i The circuit to armature 116 and series field 11S passes from positive by way of conductor 125 through series field 118, thence by way of the second highest set of contacts at 11 1 to armature 116, thence byway of conductor 126 to the lowest set of con tacts 11 1, thence back by way of the next highest set of contacts at lll to the negative feed. The circuit to the shuntfield 117 and the brake solenoid 119 (which serves to release the braking means) passes from the positive feed by 'ay of conductor 125 to the windings 117 and 119 in parallel, and thence back to the negative feed by way of the second lowest set of contacts at 114.

The energization of the hoisting means thus produced causes movement of the elevator from the 1st floor to the desired floor, in this case the second floor. At this point it should be observed that the closing of contacts at 102, which was effected by virtue of the energization of the up relay 10a controlling said contacts 102, closed a circuit thru relay 100 passing from the positive feed by way of conductor 121, contacts 102 and relay 100, back to the negative feed by way of conductor 120.

The energization of relay 100 thus produced serves to open the associated contacts at 101, thereby breaking the circuit to the gate releasing solenoid 75 just subsequent to and as a consequence of the closing of the interlock switch 106. By this arrangement selector switch 109, such action taking place by the provision of suitable mechanical means (not shown) which operate as the elevator reaches a pre-determined point adjacent the second floor level. Upon the opening of selector switch 109 in this manner the circuit to relay 94: and also to the up solenoid 104 is immediately broken and the result is the immediate deenergiz-ation of both relay 94: and solenoid 104. The deenergization of solenoid 104 causes the contacts 11 1 to assume the open position, thereby Clo-energizing the hoisting means and stopping the elevator. In this connection it is to be observed that if desired suitable retarding and leveling means may be provided to operate in coiijunction with" the main motor controlling means in any of the well-known methods.

The car now having reached the desired level where a passenger is waiting to use it and the corridor and car gates having been opened, the control means are now in condition for a repetition of the series of operations heretofore described. The description of the automatic control means, whereby the operation of the gate and door holding and closing means is interconnected with the elevator control means, has now been described with particularity in reference to I claim:

1.. In combination with an elevator hatch.- Way having a car therein, controlling means to move said car to any of said landings and to arrest the same at a selected landing", a gate on said car, means for opening and. closing said gate, a device for arresting said gate any desired point in its openn'ig movement and preventing it from moving in any direction from its'arrested position, and means for releasing said gate from the 1nfluence of said device,

2. In combination With an elevator hatch- Way having a car therein, controlling means to move said car to any of said landings and to arrest the same at a selected landing, a gate on said car, a. device for arresting said gate at any desired point in its opening movement and maintaining it in its arrested position, means for releasing said gates from the influence of said device, and means for closing said gate upon the operation of said releasing means.

3. In combination with an elevator hatch- Way having a car therein, controlling means to move said car to any of said landings and to arrest the same at a selected landing,- a gate on said car, a device for arresting said gate at any desired point in its opening movement and maintaining it in its arrested position, means for releasing said gate from the influence of said device, and means for closing said gate upon'the operation of said releasing means.

4. In combination With an elevator hatch- Way having a car therein and doors at the landings, means to move said car to any of saidlanding's and to arrest the same at the selected landing, a gate on said car, a device for arrestingand maintaining said gate at any desired point in its opening movement, a similar device for similarly controlling the door at said selected landing, and means for releasing said door from the influence of said device.

In combination with an elevator hatch- Way having a car therein and doors at the landings, means to move said car to any of said landings and to arrest the same at the selected landing, a gate on said car, a device for arresting and maintaining said gate at any desired point in its opening movement, a similar device for similarlycontrolling the door at said selected landing, and means for releasing said door from the influence of said device, said last-named means comprising an electro-maignetic element, and means to initiate the operation of said electromagnetic element as an incident to departure of said car from said selected landing.

6. In combination With an elevator hatchway having a car therein, controlling means to move said car to any of said landings and to arrest the same at a selected landing, a gate on said car, a device for arresting said closing said circuit as an incident to the op eration of said controlling means.

7. in combination with an elevator and hoisting means therefor, a gate permitting access to said elevator, gate closing means, restraining means operable at each of a plurality of points in the gates movement in the opening direction for rendering said gate closing means normally ineli ective to close the gate, and means for releasing said gateclosing means from the influence of said restraining means.

8. Apparatus as in claim 7 wherein the releasing means comprises an electr c-magnetic device and passenger controlled means for operating said device.

9. Apparatus as in claim 7 wherein the means for rendering the gate closing means normally inel'liective comprises a fluid containing chamber, a member in said fluid containing chamber connecting with said gate and means for-preventing movement of said member in one direction.

10. In combination With an elevator gate, a gate closing device comprising a spring influenced piston and piston rod, a cross head secured to said piston rod, connections from said cross-head to said gate, and means normally preventing movement of. said cross-head in the direction in Which said piston tends to move, whereby closing movement of said gate is prevented so long as said last-named means continues to operate.

11. In combination With an elevator hatchway having a car therein, controlling means to move said car to any of said land ings and to arrest the same at a. selected landing, a gate on said car, a device for arresting said gate at any desired point in its opening movement and maintaining it in its arrested position, means for releasing said gate from the influence of said device and means for operating said releasing means as an incident to the operation of said controlling means.

12. In combination with an elevator hatchway having a car therein, controlling means to move said car to anyot" said landings and to arrest the same at a. selected landing, a gate on said car, a device for arresting said gate at any desired point in its opening movement and maintaining it .in its arrested position, means for releasing said gate from the influence of said device, means for energizing said releasing means upon the'initiation of the operation of said controlling means, and means for subsequently de-energizing said releasing means before said car moves to another landing.

13. In COlllblIlittlOTl with an elevator hatchway having a car therein, controlling means to move said car to any of said land ings and to arrest the same at a selected landing, a gate on said car, a device -for arresting said gate at any desired point in its opening movement and maintaining it in its arrested position, means for releasing said gate from the influence of said device whereby said gate is allowed to move, to closed position, means for energizing said releasing means, and means for subsequently deenergizing said releasing means as said gate reaches closedposition.

14:. In combination with an elevator hatchway having a car therein, controlling means to move said ear to any of said landings and to arrest the same at a selected landing, a gate on said car, a device for arresting said gate at any desired point in its opening movement and, maintaining it in its arrested position, means for releasing said gate from the influence of said device whereby said gate is allowed to move to closed posltion, means for energizing said releasing means, and means for subsequently (lo-energizing said releasing means as said gate reaches closed position, said last-named means cmnprising an interlocking switch closed by said gate as it assumes the closed position.

15. In combination with an elevator and hoisting means therefor, a gate movable to permit access to said elevator, means for closing said gate to prevent such access, fluid pressure restraining means operable to render said gate closing means normally inetleotive to close the gate, and means for releasonce of said restraining means.

1.6. In combination with an elevator and 111g said gate closing means from the influhoisting means therefor, a gate movable to CYRUS W} BASSETT. 

